Electrical resistance welding guns are used in a wide variety of applications, such as the assembly of sheet metal parts to form an automobile body. These welding guns typically include a pair of electrodes and a mechanism for supporting the electrodes and bringing the electrodes into close proximity to create a weld.
Welding guns come in a wide variety of styles, and their design is often application-specific. For example, one style of welding gun is referred to as a “scissors” gun. A scissors gun has a pair of arms that are joined together at one of their ends. An electrode is supported at the other end of each of the arms and the arms can be pivoted relative to one another so as to bring the electrodes into close proximity, or to separate them between welding operations. Within the basic style of a scissors gun, wide variations in design are possible. The gun may be designed to mount to any of a variety of fixtures, or to a robot. The mount may be provided on the top, the bottom, the front, the rear, or either side. Various different designs of actuators may be used for moving the arms relative to one another. In some designs, one of the arms remains stationary with respect to the mount, and in others both arms move. The arm interconnection is typically referred to as a “yoke” portion. The yoke portion may be of different sizes so as to alter the spacing between the arms. The lengths of the arms may also be varied as well as the type of electrode. Various electrode types have different shapes to accommodate different applications. In addition to the above, the relative sizes and positions of virtually every component on the weld gun may be altered to suit a particular application.
Traditional welding guns are usually custom manufactured for their intended application. The welding arms, yokes, and pivots are often custom configured and may be part of a custom casting, including the arms, yokes, pivot supports, and actuator arms. Applicant's U.S. Pat. No. 6,596,958, the entire contents of which is incorporated herein by reference, provides a modular welding gun design that improves on the prior art. As described in more detail in the incorporated patent, the modular welding guns are assembled from various modular components that allow specific designs to be assembled from various more standardized parts.
With either traditional welding gun designs or Applicant's improved modular designs, significant effort is typically required to specify and design the welding guns for specific applications. The customer must specify their mounting design, the physical configuration and dimensions for the gun, the performance requirements, and other factors. The manufacturer then needs to design a gun that meets the customer's requirements, taking into consideration stress loads, actuator size and output, force at the electrode tips, and other factors. Often, the manufacturer and customer must also consider the total weight of the gun and the position of its center of gravity. In light of this, there is a need for an improved method of specifying and designing welding guns.